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White Noise

The A-Zed of Audio

The French writer Antoine de Saint-Exupéry, famous for bringing the Little Prince into the world, famously said “perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Maybe that’s why the Little Prince was from such a small planet.

This is the sort of quote you can imagine neatly screened on the wall of a super hip firm in San Francisco who designs artisanal pencils and garbage bins, working off empty desks in a restored carpet factory. Yet for the mass of our culture represented by Walmart, big box stores, McNuggets, and weekend sale madness flyers – Saint-Exupéry’s quote might as well be flying around on a little planet in outer space.

Which way forward, then? Less is more, or more is more? That’s much too huge a question for this humble blog post, but we can at least explore an unlikely hero to gain a few insights. That hero, of course, is white noise. What is that? There are more technical definitions, but let’s start off with this one: white noise is the audible version of an amphetamine junkie with an American Express Centurion Card at a busy mall on boxing day.

You’ve probably heard the term white noise before – it’s used pretty loosely to refer to ceiling fans, crashing waves, and pretty much any unpitched drone. The more technical definition is that white noise is a sound (or a signal, for those of you who get uncomfortable when people call noises ‘sounds’) which has equal energy across the entire audible spectrum. The audible spectrum consists of vibrations moving anywhere from twenty to twenty thousand times per second, and true white noise is generated randomly to fill this entire range equally.

Just as a connoisseur of wines will discern chardonnay from water, so too will a connoisseur of noises be able to discern white noise from its various coloured counterparts. But how can noise have colours?

As it turns out, it doesn’t really, but there are some colourful names for noise. White noise is only one type of noise based on the rule that it should contain equal energy across the entire spectrum, and has its name from the once-held belief that white light contains equal energy across the visual spectrum.

Equal energy across a spectrum is a very rational and clean way to design noise, but it doesn’t correspond very well to the way we hear. White noise follows a linear scale, where there’s as much energy between 1000 Hz-2000 Hz as there is between 10 000 Hz - 11 000 Hz, yet our hearing follows a logarithmic scale. If by some miracle your constitution is strong and you haven’t fainted at the mere sight of that word, I’ll quickly explain what that means. It’s not as tricky as your nightmarish math class memories probably make it seem. All logarithmic means is that we keep doubling frequencies to get equal units of measurement. So according to the way we hear, 100-200 Hz is an equal ‘distance’ as 1000-2000 Hz, which is also equal to 10 000-20 000 Hz.

The result of all this number doubling is pink noise, and it has equal energy across the audible spectrum, with the energy distributed in a way that conforms more closely to how we hear. If you listen to white noise and pink noise one after the other, the pink noise sounds more bass heavy.

If you’re waiting patiently with your pack of Crayolas , you can rejoice at the fact that noise colours don’t end at pink and white. There’s blue noise, brown noise, violet noise, and even gray noise, which is one of the most interesting because it’s the closest reflection of the way our hearing works.

When archaeologists dig up tools and relics, they can use them to get a vague sense of what life must have been like hundreds or thousands of years ago when people were using these instruments. The reason we can do this with some accuracy is that we always design our tools as a reflection of ourselves. If you found a hammer there are a number of strange things you might suppose from studying the handle, but one of them could be that its users had gripping limbs with flexible fingers and opposable thumbs. Sure, it’s nothing like a handprint cast in a Hollywood sidewalk, but it does reveal something about its user.

Noise is similar. One of the quirks of our hearing is that we’re most sensitive to midrange frequencies. This is an inheritance from hundreds of thousands of years of natural selection; human voices happen to occupy midrange frequencies. A mother whose hearing was more delicately tuned to hear her baby crying at a distance would have a higher likelihood that her genes would get passed along because her baby would be more likely to survive. Having inherited her mother’s genes, that baby would eventually have a better chance of hearing her own baby, and on and on the cycle goes until we have Jimi Hendrix playing his guitar at Woodstock with his teeth.

All of this (the sensitive hearing part, not so much the Jimi Hendrix part) – and who knows how many other evolutionary forces – results in a pattern of hearing sensitivity with a peak around the frequencies of our voices.

Gray noise is designed around this exact quirk – it has its frequency content tuned so that every range (the lows, the mids, the highs) sounds equally loud to our strange pattern of hearing. Because of this, gray noise is the auditory clay pot that we could leave behind if we wanted some alien civilization to have a sense of how we heard.

The world of noise is a strange one and there are even genres of music that use noise as their main musical content. The notion of this disorderly, meaningless sound becomes really interesting when you break it down this way; you come to realize that within the madness there’s quite a bit of order. We can have perfectly linear, mathematical noise at one end of the spectrum, or human-centric noise at the other end of the spectrum, and anything between.

Of course, in today’s information-overdriven world we often hear ‘noise’ used to label things that aren’t auditory. We use it to describe the chaotic, disorderly, excessive barrage of information that rains down upon us, most of which fits together in no meaningful way. Much like a cook who uses every single ingredient or a painter who uses every colour, we’re driven to a place where meaning-making becomes impossible.

Michelangelo (the sculptor, not the Ninja Turtle) claimed that “every block of stone has a statue inside it and it is the task of the sculptor to discover it”. Sculpture is one of the most enlightening art disciplines to consider because it has obvious examples of additive methods – clay or metal, in which a sculpture is composed of smaller elements – and subtractive methods – marble or wood, in which a figure is chiselled out of a larger block.

Music is almost always considered an additive art – we begin with silence and add sounds until we reach completion. But there’s no necessary reason to consider it this way. If white (or pink, or gray, or blue, or technicolor) noise contains within it every frequency in the audible spectrum, it means that it contains within it every piece of music ever written: all past, all future, and even the piece you may be working on right now. Perhaps then, in this strange way of thinking, it’s the job of the composer-sculptor to begin with a block of noise and remove frequencies until – as Antoine de Saint-Exupery would have it – perfection is achieved.

Jordan Mandel is a Creative Lab Instructor at the UW Stratford Campus, and writes for this blog regularly. His hobbies include echolocation, cardboard, and storing computers in clouds. More of his work can be found at jordanmandel.com/blog, which is home to the award-winning satire rag, The Outa Times.